C扩展库中回调Python函数详解编程语言

// c 程序 段 
static PyObject *gc_before_extract = NULL; 
 
/// 设置回调 
static PyObject * 
SetBeforeCallbackFn(PyObject *dummy, PyObject *args) 
{ 
PyObject *temp = NULL; 
 
if (PyArg_ParseTuple(args, "O:set_callback", &temp)) { 
   if (!PyCallable_Check(temp)) { 
    PyErr_SetString(PyExc_TypeError, "parameter must be callable"); 
   } 
   Py_XINCREF(temp);         /* Add a reference to new callback */ 
   Py_XDECREF(gc_before_extract); /* Dispose of previous callback */ 
   gc_before_extract = temp;       /* Remember new callback */ 
} 
 
return Py_BuildValue("l", (gc_before_extract == NULL) ? 0 : 1); 
} 
 
/// 调用上面函数设置的python脚本函数 
int BeforeExt(char *pBeforeExtract) 
{ 
PyObject* pArgs = NULL; 
PyObject* pRetVal = NULL; 
int    nRetVal = 0; 
 
pArgs = Py_BuildValue("(s)", pFileName); 
pRetVal = PyEval_CallObject(gc_before_extract, pArgs); 
if (pRetVal) 
{ 
   fprintf(stderr, "PyEval_CallObject : ok /r/n"); 
   nRetVal = PyInt_AsLong(pRetVal); 
   fprintf(stderr, "PyEval_CallObject : return : %d /r/n", nRetVal); 
} 
Py_DECREF(pArgs); 
Py_DECREF(pRetVal); 
return nRetVal; 
} 
 
/// 测试函数 
static  
PyObject* my_test_callback(PyObject *self, PyObject *args)  
{  
PyObject * arglist;  
PyObject * result = NULL; 
 
BeforeExt("good"); 
 
result = PyEval_CallObject(gc_before_extract, args);  
if (result) 
{ 
   Py_DECREF(result);  
} 
Py_INCREF(Py_None);  
return Py_None;  
}

/////// python 脚本 
from pyArchive import * 
from ctypes import * 
 
# 回调函数必须有一个int型的返回值 
def set_callback_fn(abc) : 
    print "t_callback_fn say : {0}".format(abc) 
    return 11 
 
CMPFUNC = CFUNCTYPE(c_int, c_char_p)  
_callback = CMPFUNC(set_callback_fn) 
 
    if SetBeforeCallbackFn(_callback): 
        print "set call back ok" 
        my_test_callback("script call : good luck") 
    else : 
        print "set call back fail"